fixup! Keep track of when and who last set the isShared flag

Author: carlobeltrame

api/src/State/CampUpdateProcessor.php

@@ -33,7 +33,7 @@ public function __construct(
 
     public function onBeforeSharingStatusChange(Camp $data): Camp {
         if ($data->isShared) {
-            $data->sharedSince = new \DateTime();
+            $data->sharedSince = new \DateTime('now', new \DateTimeZone('UTC'));
 
             /** @var User $user */
             $user = $this->security->getUser();